1. Field of the Invention
The present invention relates to the field of plant breeding and, more specifically, to the development of watermelon line 110-1005.
2. Description of Related Art
Watermelons are natural diploids, referred to as 2N (N=1), with chromosomes arranged in pairs. Many plants, including watermelons, can undergo a duplication of their entire set of chromosomes and exist as tetraploids, referred to as 4N (4N=44). Watermelon tetraploids can be produced routinely in the laboratory using cell biology techniques.
A tetraploid (4N) female parent can be crossed with a diploid (2N) male parent to produce triploid (3N) seeds (3N=33). A hybrid triploid plant produces watermelon fruit which is seedless. Although triploid plants do not usually produce any viable seed, small, white, rudimentary seeds may develop within the fruit and can be eaten with the fruit, as in the case of parthenocarpic cucumber. The number and size of the white, rudimentary seeds varies with the variety. Occasionally a dark, hard seedcoat or a true seed may be found in a triploid watermelon.
A tetraploid seed parent typically produces only 5 to 10% as many seeds as a typical diploid plant. Commercial seed production of a triploid hybrid cultivar requires a substantial amount of seed for a commercially viable product.
Tetraploid parental lines generally have a uniform or “solid” colored rind, i.e., a rind pattern that is primarily one color as opposed to a rind pattern having striping. Generally, the rind of the fruit from tetraploid parental lines has a light green to a creamy green color. This color is also sometimes referred to as “gray.”
There remains a need for improved tetraploid watermelon lines with good yield of both triploid and tetraploid seeds and which can be used to produce triploid fruit which have traits such as, for example, a small size, dark stripes or a blocky shape without end tapering.